Method for Automatically Profiling Ground in Waters

ABSTRACT

The invention relates to a method for automatically profiling ground in waters, in particular in a gravel pit by means of a floating conveying device. The inventive method consists in producing a base map on the basis a water surface map, scanning the water surface by means of appropriate devices in order to determine a bottom profile, the position and direction of said conveying device, cyclically updating the real depth of the water body and in comparing said real depth with a specified depth profile. According to said invention, predefined parameters measured near the extraction unit of the conveying device during digging layers are transmitted to a control system and the position of the conveying device is modified in the case of difference with parameters.

BACKGROUND OF THE INVENTION

The invention relates to a method for the automatic adjustment of ground profiles in waters, in particular in a gravel pit to be sunk, by means of floating conveying devices.

DE-A 199 42 472 discloses a method for the cartographically controlled sinking of waters by means of floating conveying devices. Herein, at least one base map on the base of a screen or vector map is produced from an existing water area map, in that the water is scanned by means of suitable devices for producing a three-dimensional depth profile. The position and orientation of the floating conveying device, typically a floating dredger, is determined and marked in the base map. The so formed base map is stored in the computer of the system. The water ground and, if necessary, the water bank are scanned in short intervals in the near environment of the conveying device. The data which have been obtained thereby form a depth profile. On the base of the depth profile, an updated base map will be made. Such map elements, for which the depth lines have changed due to the sinking of the water ground, will be adapted, wherein the depth profile is preferably produced as colour running profile.

Floating conveying devices, in particular floating dredgers, can have different extraction means. These ones are preferably clams, cutting wheels, bucket chains or suction pipes, wherein the material layers present on the water ground, such as for example slush or gravel, are received by the respective extraction means and brought to their further destination.

For operating a floating conveying device, in particular for changing the position, service staff is required. The staff changes the length of the traction ropes, such that the floating conveying device is brought from a first extraction position into another extraction position.

The personnel costs of the service staff are naturally a substantial part of the operating costs. But over all, a plurality of parameters (water depth on the extraction site, density and graining of the material to be extracted, water temperature, pressure in the suction pipe for suction dredgers, etc.) have to be considered and taken as base for decisions for the control of the device in order to obtain a continuous and optimum operation of the conveying device. The simultaneous consideration of all the influencing variables which are essential herein and the transformation into optimizing control commands overtaxes the capacity of the service staff and can only be realized by modern control and computer technique.

BRIEF SUMMARY OF THE INVENTION

It is the aim of the invention to put this understanding into practice in order to provide an automatic, almost staff-less and over all continuous operation with an improved extraction performance, higher extraction precision and reduced operational costs.

This aim is achieved by a method for the automatic adjustment of ground profiles in waters, in particular in a gravel pit to be sunk, by means of floating conveying devices, in that at least one base map is produced from an existing water area map, the water is scanned by means of suitable devices for obtaining a depth profile, the position as well as the orientation of the conveying device is determined, a cyclic updating of the actual water depth and a comparison with a desired depth profile are realized, wherein pre-determinable parameters of the extraction means of the conveying device are measured in the course of a layer-wise sinking operation and supplied to a control unit, and that in case of divergences from the parameters, the position of the conveying device will be changed.

DETAILED DESCRIPTION OF THE INVENTION

Depending on the material to be extracted and the extraction depth, parameters, such as the negative pressure, which is for example comprised between 0.5 and 0.8 bar, can be a corresponding threshold value. If the values remain under this threshold value, for example because no mixture, but only water is still extracted, this is a possible criterion for the fact that the position of the conveying device has to be changed. The extraction means has then namely either reached a depth, on which it must not further be lowered because of respecting a pre-determined desired depth, or it is on a mechanically maximum lowering depth thereof. Another parameter could be for example the performance characteristics of the used pump, in particular a vacuum pump, with respect to the rotational speed, performance and efficiency thereof. If, for example, the receiving area of the extraction means is clogged, this can lead to the cavitation of the pump as well as to the breakdown thereof.

Another parameter is also the flow rate of the water-solid-mixture after passage through the pump, i.e. in the subsequent pipeline.

Depending on the fact whether the decisive parameters exceed or remain beneath pre-determined limits, the control unit decides that the extraction at the given position has to be terminated. The position of the conveying device is modified automatically by the control unit which acts upon the mooring winches.

With the change of position the control unit brings the floating conveying device into a new extraction position, where material which is worth to be extracted is present according to the base map.

By means of adjustment of a certain maximum extraction depth, an economic and reasonable layer-wise extraction of the material to be extracted becomes possible. Besides, the system detects extraction obstacles, which are marked on the base map, such as for example loam banks. Such obstacles are circumvented. Finally it is also possible to intervene in the automatics of the position change by means of specified desired parameters.

In contrast to the common methods, the subject of the invention furthermore allows to produce complex harmonious ground profiles depending on the requirements of the authorizing agencies and the operators. This ability is of a special importance, since at least in the filed of wet extraction of gravel and sand, more and more ecologic requirements with respect to flat water zones as spawning or brooding zones and the like have to be met.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not as restrictive. The scope of the invention is, therefore, indicated by the appended claims and their combination in whole or in part rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

1-7. (canceled)
 8. A method for the automatic adjustment of ground profiles in water, comprising: producing at least one base map from an existing water area map; scanning the water for obtaining a depth profile and comparing actual water depth with a desired depth profile; obtaining a floating conveying device having an extraction means and an electronic control unit for controlling said floating conveying device; positioning the conveying device in a first position; providing to said control unit measurements of predetermined parameters of said extraction means during a layer-wise sinking operation; determining if said parameters are within predetermined limits; and when said parameters are not within predetermined limits, repositioning the conveying device.
 9. The method of claim 8, wherein the conveying device includes a vacuum pump, and said parameters include one or more of sinking depth, a performance characteristic curve of said pump, and a flow rate of a water-solid-mixture of extracted material.
 10. The method of claim 9, wherein said extraction means includes a suction pipe, said method includes: measuring the vacuum pressure in inside said pipe; and when said measured vacuum pressure diverges from a predetermined negative pressure, repositioning said conveying device.
 11. The method of claim 8, wherein said conveying device is automatically repositioned by the control unit after evaluation of measured parameter values and detection of parameter deviations.
 12. The method of claim 8, wherein the extraction means is moved from an extraction position into a non-extraction position before repositioning said conveying device.
 13. The method of claim 11, wherein the conveying device includes a winch controlled by the control unit, the method further comprises: electronically marking a second position to which the conveying device is to be repositioned; repositioning conveying device to the second position and maintaining the conveying device in the second position; and lowering the extraction means into a pre-determinable extraction position. 